iwlwifi: mvm: remove debugfs injection limitations

For testing features where the firmware may send some
notifications it can often be a lot easier to do that
from a test script. Remove most injection limitations
from debugfs to be able to do this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210117130510.9aff3c6b4607.I03b0ae7df094734451445ffcb7f9f0274969f1c0@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>